Consuming fats like olive oil before carbohydrates can mitigate the initial spike in blood sugar, according to new animal research. The study suggests that the order in which nutrients are consumed can influence blood sugar responses, even when the same nutrients are ingested.
A joint research team from Kyoto University, Gifu University, and Nagoya University published their findings on October 8 in the international journal Diabetes. The study analyzed the impact of the order of olive oil consumption on blood sugar levels in mice.
The researchers divided fasting mice into three groups and administered olive oil and glucose in different sequences.
- The first group received water followed by glucose.
- The second group was given olive oil first, then glucose 15 minutes later.
- The third group received glucose first, followed by olive oil 15 minutes later. The amount of olive oil administered was 5 mL per kilogram of body weight.
The results showed that mice given olive oil before glucose experienced a smaller initial spike in blood sugar compared to the other groups. Notably, blood sugar levels were lower 15 and 30 minutes after glucose administration, and the area under the blood sugar curve (AUC) for the first 60 minutes was reduced.
However, there was no difference in overall blood sugar response up to 120 minutes, indicating that the effect of consuming olive oil first primarily alleviated the rapid initial rise in blood sugar.
To understand the mechanisms behind this phenomenon, the researchers analyzed hormones involved in blood sugar regulation and gastric emptying rates.
Mice that received olive oil first showed a slower rate of food movement from the stomach to the small intestine. Additionally, there was an increase in the early secretion of hormones such as glucagon, gastric inhibitory polypeptide (GIP), and glucagon-like peptide-1 (GLP-1).
The researchers concluded that the delayed gastric emptying affected the rate at which glucose reached the small intestine, ultimately reducing the initial spike in blood sugar.
Particularly noteworthy was the role of glucagon and GLP-1. While glucagon is typically known as a blood sugar-raising hormone, this study indicated that it may work alongside GLP-1 to slow gastric emptying and suppress initial blood sugar increases.
When the researchers blocked the signals of glucagon or GLP-1 individually, the effects of consuming olive oil first were largely maintained. However, blocking both hormones simultaneously weakened the blood sugar suppression effect and eliminated the delayed gastric emptying.
Further experiments with genetically modified mice supported the interpretation that the signaling pathways of the two hormones complement each other.
The vagus nerve, which connects the brain and digestive system, was also found to play a crucial role. When the researchers severed the vagus nerve below the diaphragm on both sides of the mice, the blood sugar suppression and gastric emptying delay effects were diminished.
This phenomenon was also observed in diabetic mice. The researchers repeated the experiments with NSY mice, a model for type 2 diabetes, and STZ mice, which have significantly reduced insulin secretion, confirming that initial blood sugar spikes were alleviated in both groups.
Similar responses were noted with other fats. Mice given flaxseed oil and lard first also showed reduced initial blood sugar spikes and delayed gastric emptying. Coconut oil administration also resulted in slower gastric emptying and a tendency for reduced initial blood sugar spikes.
The researchers hope these findings will enhance understanding of the physiological principles behind how meal order affects blood sugar responses.
Previous studies involving humans have reported that consuming vegetables, proteins, or fats before carbohydrates can alleviate post-meal blood sugar spikes. This research is significant as it specifically examines the hormonal and neural mechanisms involved through animal experiments.
Professor Daisuke Yabe of Kyoto University, the lead researcher, emphasized the importance of sustainable dietary practices in daily life. He explained that adjusting the order of food intake, rather than strictly limiting certain foods, may help manage blood sugar levels.
* This article has been translated by AI.
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